In typical automobile door window installations, the portion of the door below the window opening serves as a storage well for the window when the latter is open and as a housing for the window regulator mechanism which moves the window between the open and closed positions. A wide variety of window regulator devices has been proposed for opening and closing such windows. In recent years, with the weight reduction necessary for increased energy efficiency, the design of window regulator devices has changed substantially. One change has involved the incorporation of a polymeric tape as the primary power transmission element. Such devices typically involve the interaction of a perforated tape and a sprocket moving the tape along a track. However, the perforated tape, with extended use, is subject to failure, and a continuing need exists to further reduce the width of the window regulator mechanism. Such a reduction in width has not been possible with the tape perforations that have previously been required.